For Sacramento, this is essentially a small salary clearing move. Outlaw made about $230k more than Ellington, and the Kings also got a future 2nd round pick for their troubles. The Kings did lose out on Quincy Acy, but once Eric Moreland was signed to a 3 year deal, his future in Sacramento seemed in doubt regardless due to the number of Power Forwards already on the roster.

UPDATE 1:30 pm:

Sam has clarified his article in respect to the 2nd round pick. Sacramento already owned New York's 2016 2nd round pick, but it was protected from 31-37. Those protections have now been lifted. Those protections likely wouldn't have come into play anyway, so this already unsexy deal becomes even less so. It was a trade of convenience. Instead of stretching Outlaw and waiving Acy, you save a few dollars and get rid of some restrictions.

UPDATE 3:10 pm:

Kevin Pelton posted some analysis of the trade on ESPN insider and a new tidbit of information was revealed: Apparently Outlaw wasn't eligible for the stretch provision because his deal was signed in the last CBA. Ellington however is, which saves the Kings some money this year if they use it on him.